ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades Why it is called Diazed fuse?

Never seen them either, but 13A DII fuses (color black) are mentioned in my school book too.

Link here to photos of Diazed fuses

That's very similar looking to what you'd find in old installations here. Still plenty of ancient diazed boards in service, particularly in older residential installations.

I have NEVER seen the DI or DII 13 Amp diazed fuses.

Perhaps for export markets like the UK or some of the UK colonies where ring mains are used and a 13 Amp fused plug is used. although these are more of the ceramic tube type.

Seen the odd 2 and 4 Amp DII ones on control circuits.

13 A circuits have been introduced in Germany a few years ago. So 13 A MCB's and Neozed fuses have been normed and become available now.
Suppose 13 A Diazed are normed for the same reason, but it doesn't look like there is a real market for them, as nobody would use Diazed in a new installation.

Wolfgang

What size wire do they allowe for 13 Amps ?

1.5 mm² ?

I do understand that all new intallations have MCB's now these days.

Thanks for your reply.

Pre 1988 when I lived in The Netherlands,
we used 10 Amps with 1.5 mm² and 16 Amps with 2.5 mm² wires.

Except with a combined powerpoint, lightswitch 1.5 mm² was allowed for a light circuit on a 16 Amps protected circuit.

Gruß

Raymond

Ray,
Did I get them pictures in the right order?.

@RODALCO

for D:
1,5 mm² is minimum for 3 wire 1 phase
2,5 mm² minimum only for 5 wire 3 phase (mandatory only for range/cooker/oven in kitchen)

> 95 % of actual domestic MCBs are B16, the rest is for direct water heaters B25, B32 (4 or 6 mm² typically)

even B10 is rather rare (more expensive than B16)
N is never switched <-> NL+F, nor protected (B), although allowed.

Situation in Austria is more reasonable. But that's Rangers' topic.


In front of switch panel and counter you will find an E characteristic selective circuit breaker now. Used to be Neozed so far. Mains service is usually fused by NH 63A or more.

Grid is TN-C-S or TT depending on local line provider (VersorgungsNetzBetreiber)

They're _really_ rare by now, but once or twice I've seen 4A DII in domestic fuse boxes.
As a matter of fact, fuses 6A and below are _not_ stepped, i.e. they all have the same tip diameter!

Austria: we've got differen requirements for fuses/L characteristic breakers and B/C/D breakers.
1.5mm2: L/fuse: max. 12A, that's why we used to have 12A breakers. B/C/D breakers: max. 16A but depends on the installation method (insulated walls, for example drywall with rock wool call for derating). 2.5mm2: L 20A (though usually 16A max), B/C/D 25A (though rarely ever more than 20A, rather 16).
Neutral usually fused or switched on single phase circuits.